1. The Field of the Invention
The present invention relates generally to apparatus for producing a stereoscopic optical image, and more particularly, but not necessarily entirely, to a laparoscope utilizing three or more selectable optical imaging assemblies to provide a stereoscopic view of the internal regions of the human body in a direction non-parallel to the axis of the laparoscope.
2. Description of Related Art
Modern surgeons seek to perform necessary surgical procedures on a patient while minimizing the disturbance and destruction to intervening tissues and organs. To this end, medical endoscopes have been developed as an aid to diagnostic, surgical and other medical procedures. Medical endoscopes enable visual examination of body channels, cavities, spaces and internal organs through a natural opening or small incision, and thus without conventional surgery.
Medical endoscopes are also useful for visual observation during surgery. Specific endoscopes have been developed for access to various body lumens and cavities. For example, laparoscopes, bronchoscopes, sigmoidoscopes, gastroscopes, and so forth, are all available. The main difference between these devices is the size of the instrument. However, the general configuration and method of use of such scopes are quite similar. Many of the body cavities and hollow conduits (e.g. peritoneal, abdominal, bronchial, lung, esophagal, etc.) can thus be accessed through endoscopic means, without surgical incisions and the resulting trauma to the patient.
Endoscopes typically include a long, thin tubular casing optically connected to a viewing mechanism. The tubular casing is narrow enough to insert through a small natural or surgical opening in the body. When the endoscope is inserted and positioned for use, an image of the object being viewed is formed at an inserted end thereof by an objective lens. The image is passed through a series of relay lenses down the cylinder to an eye lens or video camera at a viewing end of the endoscope. A major drawback to using an endoscope as a surgical aid is that it gives a monocular view and therefore no depth perception. Surgical procedures such as suction, irrigation, biopsy, incisions, suturing and cutting must be learned without the benefit of three dimensional visualization.
Endoscopes have recently been developed that produce the illusion of three dimensions or depth by combining two dimensional images. The stereoscopic effect is created by producing two optical images of the desired region, each image having a different point of view, such as a left image and a right image. It is known to incorporate two separate optical fiber bundles in parallel inside a single casing to add the advantages of fiberoptics to stereoscopic viewing. The two images are carried by the two optical fiber bundles, respectively, to left and right image sensors, which may comprise charge-coupled device (CCD) cameras or other image sensing devices. The sensing devices convert the left and right optical images into left and right video images, respectively. The video images are then presented as alternating left-right images on a viewing monitor to the user to thereby create a stereoscopic or three-dimensional optical view. The right and left images may also be referred to as the first side image and second side image, repectively.
Although endoscopes known in the prior art have succeeded in producing a stereoscopic or three dimensional effect, they are characterized by a number of disadvantages. Many of the devices known in the prior art only provide two non-moveable optical imaging assemblies. Two non-moveable assemblies do not allow the user to adjust for viewing objects at different distances. If an object is too close, a cross-eye feeling is experienced by the user, and if the object is too far distant, the three dimensional perception diminishes to an irrelevant value.
In an attempt to provide variable depth perception views, U.S. Pat. No. 6,306,082 (granted Oct. 23, 2001 to Takahashi et al.) discloses an endoscope that allows the user to view multiple selectable images, but this device has limited usefulness for viewing areas with a narrow portal entry space. The design of this device is less effective because the distance between optical image systems cannot be greater than the diameter of the endoscope. Furthermore, the prior art requires a relay system between the objective lens and the image receiving means, which adds to the cost and complexity of the device.
Other devices known in the art attempt to provide variable depth perception with two optical imaging assemblies that are moveable in relation to the other. These devices requires complex electronic control circuitry to provide movement and synchronization. These devices are expensive to manufacture and complex in operation.
It is noteworthy that none of the prior art known to applicant provides a stereo laparoscope capable of providing multiple, selectable depth perception views where the distance between the optical assemblies is not limited by the diameter of the endoscopic instrument and where a relay system between the objective lens and the image receiving means is not necessary. There is a long felt need, illustrated by the disadvantageous endoscope devices currently known, for an endoscope that is inexpensive to make, simple in operation and which provides multiple, selectable depth perception views without a relay system of areas where the portal entry space is limited.
The prior art is thus characterized by several disadvantages that are addressed by the present invention. The present invention minimizes, and in some aspects eliminates, the above-mentioned failures, and other problems, by utilizing the methods and structural features described herein.
The features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the invention without undue experimentation. The features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims.